hurricane sandy. and now after the hurricane, then the snow. now it feels like spring while winter hits out west. risk factor, a reality check tonight from dr. nancy snyderman on the story in the news today about pregnancy, the flu, and autism. >>> and behind the wheel, tonight how women are taking the lead. this has to do with a huge change that has happened slowly on the american roads. nightly news begins now. >>> good evening, the damage, both personal and political, continues to pile up following the resignation of the director of the cia, retired four-star general david petraeus. easily the most celebrated general officer of a generation. and now, the questions are rolling in about the extramarital affair that led to all of this, about the e-mails that led the fbi to petraeus. and how much further this all goes. we begin our reporting of the story tonight with nbc's andrea mitchell in our washington news room, good evening, andrea. >> reporter: good evening, brian, new questions tonight on why the fbi did not tell the president or the intelligence leaders about the involvement of petr